Earth boring apparatus



Sept. 3, 1957 Filed NOV. 22, 1954 FEE III

0. GILES EARTH BORING APPARATUS 3 Sheets-Sheet 1 INVENTOR.

04g 6 (lies Sept. 3, 1957 o. GILES EARTH BORING APPARATUS v 3Sheets-Sheet 3 Filed Nov. 22, 1954 Ira/671252": Ulqg Giles EARTH BORINGAPPARATUS Oley Giles, Glendale, Califl, assignor to Borg-WarnerCorporation, Chicago, 111., a corporation of Illinois ApplicationNovember 22, 1954, Serial No. 479,456

3 Claims. (Cl. 255-28) The present invention relates in general to earthbore drilling apparatus and more particularly to an earth boring drillof the type employing a vertically reciprocating drill rod and bit whichvibrates at a frequency substantially equal to the resonant vibrationfrequency of the rod and bit.

More particularly, the present invention is intended to provide anauxiliary device adapted to be utilized in conjunction with earth boredrilling apparatus of the general type disclosed in the patent to A. G.Bodine, 2,554,005.

In earth boring apparatus of the type disclosed in the aforementionedBodine patent, suitable vibration generating mechanism is utilized forgenerating sonic vibrations in the drill rod and bit in order to providethe necessary force to eliect the drilling operation. In such drillingdevices, the vibrating bit is maintained in engagement with the bottomof the well hole and the formation immediately adjacent to the bit isshattered either due to vibrations imparted thereto by the bit itself ordue to the percussive action of the bit on the formation. In a drill ofthis type the bit reciprocates or vibrates vertically at very nearly theresonant frequency of the massive drill rod and bit and the amplitude ofthe vibrating bit is of the order of three sixteenths to approximatelyone-half inch.

As is customary in oil well drilling operations, a suitable mud fluid ispumped into the well hole downwardly through the drill string and drillrod, with the mud fluid emerging from the bottom of the drill rod beingforced out of the well hole upwardly around the drill rod and drillstring inside of the well hole. As the mud fluid rises in the well holein this manner it takes with it the formation fragments which have beenbroken up by the bit. When the well hole reaches a depth of severalthousand feet, the hydrostatic pressure existing at the bottom of thewell hole, due to the long column of mud fluid, is considerable and isof the order of several thousand pounds per square inch. Further, themud fluid is substantially incompressible. Due to this fact, Withoutsome means being provided for acoustically disconnecting or decouplingthe mud fluid from the drill rod and bit, substantially all of theenergy which is put into the drill rod and bit by the vibratorymechanism is consumed by the pressure surges of the mud fluid in thewell hole resulting from sound waves generated in the mud fluid at thebottom of the well hole by the vibrating drill rod and bit.

The present invention has for its principal object to provide aneffective means for acoustically disconnecting or decoupling a sonicallyor an acoustically vibrating drill rod and bit, disposed in a well holewith the bit in substantial engagement with the bottom of the well hole,from the column of mud fluid in the well hole utilized for the purposeof flushing or washing out the chips and fragments of the formation atthe bottom of the well hole which are loosened or broken up by thevibrating bit.

More specifically, the principal object of the present invention is toprovide an improved form of acoustic or sonic decoupler'cell of thegeneral type disclosed in the nitcd States Patent 2,805,044 PatentedSept. 3, 1 957 copending application of J. P. Selberg and G. D. Currie,Ser. No. 360,706, filed June 10, 1953, which issued as Patent No.2,771,270 on November 20, 1956.

A more particular object of the present invention is to provide adecoupler cell of the type mentioned in the immediately precedingparagraph wherein the compressible chamber comprises a flexible membranedisposed within an apertured enclosing casing in order to admit the mudfluid against the flexible membrane so as to permit the compressiblechamber to absorb the pressure surges of mud fluid resulting from soundwaves generated therein by the vibratory drill rod and bit. In furtherparticularity the flexible membrane comprises a flexible rubber memberhaving hard rubber inserts therein disposed opposite the apertures inthe enclosing casing for preventing extrusion of the membrane throughthe casing apertures when the pressure within the chamber exceeds thepressure outside the chamber.

Numerous other objects and advantages of the present invention Willbecome apparent from the following de tailed description when read inconjunction with the accompanying drawings wherein:

Fig. 1 is a view showing an earth bore drilling derrick for supportingthe drilling apparatus of the present invention within a well bore;

Fig. 2 is a view showing the lower end of a drilling string supported bythe derrick of Fig. l and having a decoupler cell of the type disclosedherein included as an integral part of the drill string;

Fig. 3 is a view showing the general features of the decoupler cellcomprising the subject matter of the present invention;

Figs. 4A and 4B comprise detailed sectional views showing the decouplercell of Fig. 3 on an enlarged scale; I

Fig. 5 is a detailed sectional view taken substantially along the line55 in Fig. 4A and looking in the direction of the arrows;

Fig. 6 is a sectional view taken substantially along includes a derrick10, draw works 11, driving rotary table 12, kelly 13 extending throughtable 12, swivel 14 coupled to the upper end of the fluid passagethrough kelly 13, and hook 15 supporting the bail of swivel 14. The hook15 is suspended through a travelling block 16 and cable 17 from the topof the derrick 10, and the cable 17 is wound on the usual hoisting drumof the draw works 11. Mud fluid, such as is conventionally employed inrotary oil well drilling operations, is pumped through a supply pipe 18from a supply tank or sump 19 and is delivered under pressure by a pump20 through a pipe 21 and hose 22 to the goose neck of swivel 14, andfrom this point the mud fluid flows down through the kelly 13. andthrough a drill pipe string 23 coupled to the lower end of the kelly 13.

The kelly 13 and the drill string 23 extend into a bore hole 24 whichextends downwardly into the earth. The bore hole 24 is lined for asuitable distance 'down from the ground surface by surface casing 25which is supported by a landing flange 26 resting on a concrete footing27 in the bottom of a pit 28. A blow-out prevente'r 29 is mounted at thehead of the casing 25 and a riser 39 above the blow-out preventer 29 isiprovidetl with a 31 is shown as discharging to a conventional vibratorymud screen 32, and the mud is led from the latter back to 3? meansof ,apipe line 33.

The drill pipe string 23 coupled at the lower'end Ofgthe kelly 13comprises a conventional drill pipe string and it will be understoodthat this pipe string is made up of a number of usual drill pipe lengthscoupled together by the usual tool joints as indicated at 34. v Thedrill pipe string 23 also includes suitable driving motor means and avibration generator assembly (not shown) of the type disclosed in theaforementioned patent to Bodine 2,554,005. It will suflice to stateherein that the motor and vibrator are capable of vibrating the drillrod and bit below at a frequency approximately equal to the resonantvibration frequency of the drill rod and bit. For further description ofthe motor and vibrator, reference should be had to the aforementionedBodine patent.

At some point below the motor and vibrator assembly, the drill pipestring 23 includes a massive elongated elastic longitudinally vibratorydrill rod 37. The longitudinally vibratory drill rod 37 is ofsubstantial mass and length and it is contemplated that it will be madeup of a plurality of steel drill collars 38, which are connectedtogether by means of conventional tool joints 34. It is contemplatedthat one of the drill collars 38a will be provided with an acoustic orsonic decoupler cell comprising the subject matter of the presentinvention and described in detail in connection with Figs. 36. At thebottom of the drill rod 37, a bit 39 is provided, which may be of anywell-known type. The bit 39 is of conventional construction and detaileddescription thereof in the present case is not deemed necessary in orderto understand the present invention.

The decoupler cell disposed in the drill collar 38a and comprising thesubject matter of the present invention shown in Figs. 3-6 will bedescribed.

The drill collar 38a is internally threaded, as indicate at 46, for thepurpose of engaging corresponding external threads on the next drillcollar section 38 above. It will be noted that the drill collar 38a isalso provided with internal threads 40a at its lower end for providingmeans for connecting the next lower drill collar 38 thereto.

The decoupler cell mounted within the drill collar 3dr: comprises anupper chamber 41 and a lower chamber 42. The upper chamber 41 is formedwithin a cylindrical sleeve 43 which fits snugly within the drill collar38a and which is prevented from moving upwardly within the drill collar38a by means of an internal nut 44 threaded into the upper threadedregion 4t) on the drill collar 38a. Mounted concentrically within thesleeve 43 is an internal sleeve 45 formed with a plurality ofperforations or apertures 46 therein. Both of the sleeves 43 and 45 abuta disc 47 disposed against the nut 44 and suitable pins 48 and 49 holdthe sleeves 43-and 45 from rotation. The external sleeve 43 is formed ateach end with a radially inwardly projecting shoulder 56, with theshoulders respectively being cut away, as indicated at 51 and 52. Aflexible rubber membrane 53 is positioned between the shoulders 59 onthe external sleeve 43 and the inner sleeve 45, the rubber membrane 53being adapted to fit snugly between the two sleeves so as to eflect aseal between the external sleeve 43 and the rubber membrane 53.

The lower chamber 42 of the decoupler cell is formed by an internalsleeve 55 having annular members 56 and 57 welded thereto. The annularmembers 56 and 57 are cut away, as indicated at 53 and 59 respectively,in order to receive a flexible rubber membrane 60 between the annularmembers 57 and 58 and the drill collar 38a. The membrane 60 fits snuglybetween the annular members 5'7 and 58 and the drill collar 38a so as toprovide the sealed chamber 42. A plurality of perforations or apertures61 are formed in the drill collar 38a adjacent the flexible membrane 60.

Suitable means are provided for filling each of the decoupler cellchambers 41 or 42 with any desired gas under pressure. This means willnow be described. The shoulder 50 is drilled as indicated at 62 toprovide a passageway for admitting the gas into the chamber 41 and thepassageway 62 communicates with a valve 63 having a fluid-tightclosure-cap 64 threaded into a suitable opening in the drill collar 38afor insuring that the chamber 41 will be sealed.

The annular member 57 is drilled 'as indicated at 65 to provide apassageway for admitting'gas into the chamber 42 by means of a valve 66adapted to be closed by a cap 67 threaded into an opening in the drillcollar 38a.

In the operation of the. decoupler comprising the subject matter of thepresent invention, the drill collar section E ois lowered into earthbore 24 and, as will be apparent, the pressure of the mud fluid pumpedinto the earth bore 24 through the drill string 23 increases withincreasing depths of the bore 24. Therefore, the chambers 41 and 42 arefilled with a gas under a pressure substantially equal to or'slightlygreater than the pressure of the mud fluid at the depth at which thedecoupler cell is to operate. Thus, when pressure surges are created inthe mud fluid due to the vibratory drill rod 37, the surging mudfluidmay communicate with the rubber membranes 53 and 55 through theapertures 46 and 61 respectively. The flexible chambers 41 and 42 aretherefore effective to dampen the pressure surges which are created inthe mud fluid at the bottom of the wellhole. v 7

It will be apparent that as the decoupler cell is withdrawn from theearth bore hole or while it is being inserted therein, there is asubstantially greater pressure existing within the chambers 41 and 42than exists in the area around the chambers. As a result, there is atendency for the increased pressure of the gas within the chambers 41and 42 to urge the flexible membranes against the apertured sleevesrespectivelyand this tends to cause extrusion of the flexible membranethrough the apertures 46 and 61. The present invention discloses meansfor minimizing this tendency for the flexible membranes to be extrudedthrough the decoupler cell apertured sleeves.

Referring to Figs. 7 and 8, the rubber membrane 60 is disclosed ingreater detail. This membrane comprises alternate strips of relativelysoft flexible material indicated by reference numeral 68 and relativelyhard strips of rubber 69 designed to be disposed opposite the aperturesin the enclosing casing for the decoupler cell. The hard rubber strips6? are more resistant to extrusion through the openings in the enclosingcasing for the decoupler cell while the relatively soft rubber strips 68provide the necessary flexibility for the membrane 60. In the specificform disclosed, very thin bonding sleeves 70 are provided with thestrips 68 and 69 alternately disposed between two of the bonding sleeves7t) and with a second group of the strips 68 and 69 being bonded on theother side of one of the bonding sleeves 79. This merely represents onemanner in which the sleeve 60 could be formed. In one specificapplication it has been found that the bonding sleeves 70 may be made ofa strong flexible material, known commercially as butyl while the softflexible strips 68 may be made up of a rubber known commercially asBuna-N and the hard strips 69 may be made of a relatively harder rubberknown commercially as 560.

The important feature of the present invention is that the sleeves 60 beprovided with alternate longitudinally extending strips of relativelysoft and hard flexible material so that the hard strips may be disposedopposite the openings in the decoupler cell sleeve so as to preventextrusion of the sleeve through the openings when the pressure withinthe cavity or chambers exceed the external pressure.

It will be understood that both flexible sleeves 53 and 60 will beconstructed in the manner shown in Figs. 7 and 8 so that the desirablefeatures disclosed herein will be present in each of the flexiblesleeves.

It is contemplated that numerous changes and modification may be made inthe present invention without departing from the spirit or scopethereof.

What is claimed is:

1. Sonic decoupling means adapted to absorb energy consuming pressuresurges of mud fluid in a well hole in the earth caused by sound wavesgenerated by a longitudinally vibrating drill rod and bit, wherein thebit is dis posed in contact with the bottom of the well hole and isvibrating at a frequency approximating the resonant vibra tion frequencyof the rod and bit, and comprising a decoupler cell adapted to besecurely mounted in concentric relation to said drill rod in a regionthereof which is subject to said energy consuming pressure surges in themud fluid, said decoupler cell including means defining a resilientcompressible chamber adapted to be cyclically compressed at thevibration frequency of the rod and bit for thereby absorbing saidpressure surges of the mud fluid caused by the sound waves generated bythe vibrating rod and bit, an enclosing casing disposed around saidcompressible chamber and being formed with a plurality of aperturestherein for admitting the mud fluid to the compressible chamber, andsaid compressible chamber comprising a flexible membrane having hardinserts therein disposed opposite said casing apertures for preventingextrusion of the membrane through said apertures when the pressurewithin the chamber exceeds that outside the chamber.

2. Sonic decoupling means adapted to absorb energy consuming pressuresurges of mud fluid in a well hole in the earth caused by sound wavesgenerated by a longitudinally vibrating drill rod and bit, wherein thebit is disposed in contact with the bottom of the well hole and isvibrating at a frequency approximating the resonant vibration frequencyof the rod and bit, and comprising a decoupler cell adapted to besecurely mounted in concentric relation to said drill rod in a regionthereof which is subject to said energy consuming pressure surges in themud fluid, said decoupler cell including means defining a resilientcompressible chamber adapted to be cyclically compressed at thevibration frequency of the rod and bit for thereby absorbing saidpressure surges of the mud fluid caused by the sound waves generated bythe vibrating rod and bit, an enclosing casing disposed around saidcompressible chamber and being formed with a plurality of rows ofapertures therein for admitting the mud fluid to the compressiblechamber, and said compressible chamber comprising a flexible membranehaving elongated hard insert strips therein disposed opposite said rowsof casing apertures for preventing extrusion of the membrane throughsaid apertures when the pressure within the chamber exceeds that outsidethe chamber.

3. Sonic decoupling means adapted to absorb energy consuming pressuresurges of mud fluid in a well hole in the earth caused by sound Wavesgenerated by a longitudinally vibrating drill rod and bit, wherein thebit is disposed in contact with the bottom of the well hole and isvibrating at a frequency approximating the resonant vibration frequencyof the rod and bit, and comprising a decoupler cell adapted to besecurely mounted in concentric relation to said drill rod in a regionthereof which is subject to said energy consuming pressure surges in themud fluid, said decoupler cell including means defining a resilientcompressible chamber adapted to be cyclically compressed at thevibration frequency of the rod and bit for thereby absorbing saidpressure surges of the mud fluid caused by the sound waves generated bythe vibrating rod and bit, an enclosing casing disposed around saidcompressible chamber and being formed with a plurality of rows ofapertures therein for admitting the mud fluid to the compressiblechamber, and said compressible chamber comprising a flexible rubbermembrane having relatively hard rubber insert strips therein disposedopposite said rows of easing apertures for preventing extrusion of themembrane through said apertures when the pressure Within the chamberexceeds that outside the chamber.

References Cited in the file of this patent UNITED STATES PATENTS GreatBritain Apr. 21, 1954

